The timing could hardly have been worse. Already grappling with a string of attacks by a violent Islamist group in recent weeks, Nigeria's government now faces an indefinite mass strike and protests that threaten to shut down the country.

Thousands in Africa's most populous nation have poured onto the streets since the government announced on 1 January that it would discontinue a state fuel subsidy programme, which has kept fuel cheap for decades – but diverted valuable funds needed to invest in infrastructure for Nigeria's booming population.

Overnight, petrol pump prices in Africa's largest oil-producing country more than doubled to about $1 per litre.

With the fuel subsidy eating into a quarter of the annual budget, the government says it will save £4.2bn annually to invest in underperforming refineries that have forced Nigeria to import its own oil once it has been refined.

Seun Kuti, the son of afrobeat musician and vocal anti-government critic Fela Kuti, said he would lead supporters through the choked streets of Lagos on Monday.

"I'm not talking economics here, I'm just talking common sense," he said, as he handed out flyers to students, labourers and market workers who planned to attend the rally. "You cannot charge $1 a litre when the [majority of the] population lives on less than a dollar a day."

Defying a court injunction that banned the strikes because they are unrelated to a labour dispute, leaders of the country's largest trade union asked more than 2 million members to begin an "indefinite" strike on Monday, which could paralyse road and air traffic and shut down power grids.

Armoured police vehicles – many already in place after sectarian bombings killed dozens across the country in recent weeks – fanned out across the capital, Abuja, and other major cities ahead of the strikes.

Security sources say 15,000 police will be deployed in the capital, Abuja, on Monday.

President Goodluck Jonathan attempted to quell the growing public discontent in a special televised address late on Saturday. "I personally feel pained to see the sharp increase in transport fares and the prices of goods and services. If I were in your shoes at this moment, I probably would have reacted in the same way," he said, before announcing a 25% pay cut for cabinet ministers.

His administration argues that the subsidy hands over billions of dollars annually to a cartel of fuel importers, while dampening appetite for private investment in Nigeria's under-performing refineries.

"I understand fully well that deregulation is not a magic formula that will address every economic challenge, but it provides a good entry point for transforming the economy," the president said.

Jonathan, who took office in May last year, has struggled to win over weary Nigerians who have rarely benefited from the nation's two million barrel-per-day oil industry. The president's belated address to the nation has been largely drowned out by a storm of debate across radio and TV shows.

Calls from Nigerians with access to Facebook and Twitter accounts – a minority in a country where 70% live on less than $2 a day — for sit-in movements similar to the Occupy Wall Street movement in the United States have gained steady momentum in major urban centres.

But the debate has spawned vocal critics on either side of the divide. Student Onyewu Ahubi asked: "Where were these protestors when education funding was being cut? Is it only because they can't fill up their big cars now they are protesting?" He said protests were lacklustre in the largely rural state of Benue, where pump prices routinely outstrip those in urban centres.

The planned shutdown comes amid a state of emergency declared in the several northern states after the violent Islamist group Boko Haram stepped up a long-simmering insurgency when it attacked four churches simultaneously on Christmas day. The group has killed at least 40 people in the past two weeks, threatening to ignite a sectarian civil conflict.

Bismarke Rewane, a former economic advisor to the President said, the government lacked credibility among Nigerians. "We have a political and sectarian crisis both looming at the same time. Even if the strike is called off by labour unions, I don't think the protests will go away. Right now people are united because of the common pain," he added.